This study has investigated the inactivation of polyphenoloxidase (PPO) in peach puree during thermal (50–60 °C, 2–30 min) and combined high pressure‐mild thermal treatment (HPMT) (200–600 MPa, 25–45 °C, and 2–23 min). HPMT resulted immediately after treatment in an increase in PPO activity up to 66.50% at 200 MPa and 45 °C compared with the untreated samples. The reaction order (nth) of PPO thermal inactivation was 1.951 (0.1 MPa, 50–60 °C) and 0.953 for the HPMT treatment (200–600 MPa, 25–45 °C). Fractional kinetic models were applied in PPO thermal (~89% labile fraction, 11% stabile fraction) and HPMT inactivation (up to ~67% stabile fraction at 200 MPa, 25 °C). The activation energy estimated for the thermal inactivation in 50–60 °C range at 0.1 MPa was 148.26 kJ/mol, while for the HPMT inactivation varied from 82.31 kJ/mol at 300 MPa to 226.16 kJ/mol at 500 MPa. A third order polynomial model described the PPO inactivation by HPMT.
Practical application
Inactivation of polyphenoloxidase (PPO), enzyme responsible for browning is a mandatory condition for maintaining quality of the processed fruits. As this enzyme is generally known to display variable thermal and/or barostability, depending on the type of food matrix, kinetic data are required to optimize the processing parameters. The data on peach puree PPO and the models provided in the current study could help producers to identify the optimum peach processing condition necessary for the inactivation of PPO by high pressure‐mild thermal treatment, leading to the extension of puree shelf life. However, methods for limitation of the oxygen presence in the peach puree mixtures should also be employed during processing and storage.
Decontamination of egg shells is required to improve the microbiological safety of the fresh hen eggs used for human consumption or for hatching. Conventional chemical decontamination methods involving quaternary ammonium disinfectant, sodium hydroxide, phenol, hydrogen peroxide or formaldehyde, leave residues on egg shells that may damage the cuticle layer. Therefore new techniques of egg shells decontamination, such as ultraviolet (UV) radiation, have been developed. This review aims to evaluate the data from available literature and to provide a general review of UV light treatment application for egg shell decontamination. Data shows that UV treatment was effective for the inactivation of the bacterial population present on clean egg shells and recently contaminated shells. Combined treatments such as UV light with ozone or hydrogen peroxide (H 2 O 2 ) improved the inactivation of microorganisms. Recent advances in science and engineering indicate that treatment with UV light has a competitive advantage in comparison with traditional egg shell sanitation treatments for decontamination. Chicken eggs are composed of about 9.5% protective shell, 63% albumen (egg white), and 27.5% vitellus (egg yolk). The calcium carbonate in shell makes it tough and, as a consequence, protects the integrity of the inner egg. Egg white consists primarily of 88% water into which are dissolved 11% proteins, including albumins, mucoproteins, and
An in-depth analysis of wheat flour (WF) substituted with 0.5–2.5% rosehip powder (Rp) concerning the proximate composition, dough farinographic properties, and bread physico-chemical characteristics was performed. The purpose of this study was to investigate whether the use of Rp as a natural alternative for synthetic ascorbic acid in breadmaking was appropriate. A sample of wheat flour with an ascorbic acid addition of 2 mg/100 g was also used. Rp showed higher ash, carbohydrates, and fibre content, as well as lower moisture and protein content compared to wheat flour, and a vitamin C content of 420 ± 16.09 mg/100 g. A proximate composition analysis revealed a decrease in moisture, protein, and wet gluten, and an increase in ash, carbohydrates, and fibres for the flour mixtures compared with WF. Farinographic properties were positively influenced by the Rp addition and the high fibre content in the flour mixtures. Water absorption increased from 58.20% (WF) to 61.90% (2.5% Rp). Dough stability increased for the 0.5–1.0% Rp addition, then slightly decreased. The physico-chemical properties of bread prepared from flour mixtures showed a significant increase in height: 100.10 ± 0.14 mm (WF)–115.50 ± 0.14 mm (1.5% Rp), specific volume: 142.82 cm3/100 g (WF)–174.46 cm3/100 g (1.5% Rp), moisture: 41.81 ± 0.40% (WF)–43.92 ± 0.15% (2.0% Rp), and porosity: 87.75 ± 1.06% (WF)–89.40 ± 0.57% (2.5% Rp). The results indicated that the Rp used in breadmaking to replace synthetic ascorbic acid could be suitable.
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